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Which statement among the following are ...

Which statement among the following are correct ?
I. `Ce^(+3)` is an oxidizing agent & colourless.
II. `Lu^(3+)` is colourless.
III. Actinoids exhibit a higher number of oxidation states than lanthanoid
IV. All 3d elements give `H_(2)` with 1 M HCl

A

II, III

B

I, III

C

I, II, III

D

I,IV

Text Solution

AI Generated Solution

The correct Answer is:
To determine which statements among the given options are correct, we will analyze each statement one by one. ### Step-by-Step Solution: 1. **Statement I: `Ce^(+3)` is an oxidizing agent & colourless.** - **Analysis:** Cerium in the +4 oxidation state (`Ce^(+4)`) is known to be a good oxidizing agent. However, `Ce^(+3)` is not an oxidizing agent; it is the reduced form of cerium. Additionally, `Ce^(+3)` is typically colorless due to the absence of unpaired electrons. Therefore, this statement is **incorrect** because `Ce^(+3)` is not an oxidizing agent. 2. **Statement II: `Lu^(3+)` is colourless.** - **Analysis:** Lutetium in the +3 oxidation state (`Lu^(3+)`) is indeed colorless. This is due to the absence of unpaired electrons in the 4f subshell, which means it does not absorb visible light. Therefore, this statement is **correct**. 3. **Statement III: Actinoids exhibit a higher number of oxidation states than lanthanoids.** - **Analysis:** Actinoids can exhibit a wider range of oxidation states compared to lanthanoids due to the involvement of 5f, 6d, and 7s electrons in bonding. This is because the energy levels of these orbitals are close enough to allow for the loss of varying numbers of electrons. Therefore, this statement is **correct**. 4. **Statement IV: All 3d elements give `H_(2)` with 1 M HCl.** - **Analysis:** Not all 3d transition metals react with hydrochloric acid to produce hydrogen gas (`H2`). For example, copper is less reactive than hydrogen and does not displace it from HCl. Therefore, this statement is **incorrect**. ### Conclusion: - **Correct Statements:** II and III - **Incorrect Statements:** I and IV Thus, the correct answer is that **statements II and III are correct.**
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